1. Field of the Invention
The present invention relates in general to a method of filling an ink cartridge with ink.
2. Discussion of Related Art
As disclosed in U.S. Pat. No. 6,786,581 B1, US 2002/060725 A1, and US 2004/233260 A1 corresponding to JP-A-2001-113723, an ink cartridge is installed on an ink-jet recording apparatus and ink in the ink cartridge is consumed in accordance with print operation performed by the ink-jet recording apparatus. When the ink in the ink cartridge is completely consumed, the ink cartridge which has been used is replaced with a new ink cartridge purchased by a user and the used ink cartridge is discarded. The discard of the used ink cartridge, however, undesirably results in environmental contamination and wasteful consumption of finite resources on the earth. Accordingly, there is a demand for recycling of the used ink cartridge. An ink cartridge disclosed in the above-indicated US documents is provided with a valve device which is kept in its closed state in an ordinary condition by means of a spring. When the ink cartridge is mounted on a recording apparatus, the valve device is placed in its open state, whereby ink in the ink cartridge is supplied to the recording apparatus. Where the ink in the ink cartridge is used up, the ink cartridge can be filled with ink through the valve device by placing the valve device in its open state. For placing the valve device in its open state with high reliability, however, it is required to use a jig suitable for the valve device.